1. Field of the Invention
This invention relates in general to covers for the beds of pick-up trucks and more particularly to an extensible cover for use on the bed of a pick-up truck which has a 5th wheel trailer hitch mounted in the floor of the bed.
2. Description of the Prior Art
The prior art is replete with covers for pick-up truck beds ranging from canvas-like covers held in place by snaps to considerably more expensive and complex covers such as a rigid molded plastic cover which is hinged at the front end of the bed. The various types of covers all have some drawbacks. For example, the canvas-like covers mentioned above, sometimes referred to as a tonneau cover, provided virtually no security for articles contained in the bed other than hiding them from view. Also, the only way that relatively large articles, e.g. those which stick up above the sides of the bed, can be carried in a pick-up bed that is equipped with a tonneau cover is to remove the cover. The hinged plastic cover provides the desired security but does not make any provisions for carrying large objects. Also, these prior art covers all, more or less, present some problems with regard to access to the pick-up bed for insertion and removal of articles carried in the beds of the trucks.
A particular prior art bed cover which overcomes many of the problems usually associated with pick-up truck bed covers, is fully disclosed in U.S. Pat. No. 3,675,885; 4,613,181; and 4,673,209. These covers are in the form of a rigid structure which is attached by four special spring-loaded arms located at the corners of the bed of a pick-up truck. The arms are designed to fold inwardly relative to the bed of the pick-up truck and when all four arms are folded inwardly, the cover will be in its lowered position wherein it will be in resting engagement with the upper ledges of the bed and the cover is provided with means for being locked in its lowered position. By lifting one side or the other of the cover so as to unfold the two arms on the lifted side, the cover will be moved into a tilted partially elevated position so that access to the contents of the pick-up bed can be obtained from either side thereof. When both sides of the cover are lifted so as to unfold all four arms, the cover will, of course, be in the fully elevated position and this provides sufficient clearance for virtually any large objects. When the cover is fully elevated, the arms may be locked in their unfolded extended states to allow the pick-up to be driven with the cover elevated.
As is well known in the art, many pick-up truck owners are using what is commonly known as a 5th wheel trailer hitch for towing purposes, and several configurations of such hitches are commercially available. Briefly, a 5th wheel trailer hitch is a mechanism that is mounted in the bed of the truck and is often connected to the frame of the truck for strength reasons. When towing a trailer with such a hitch, the front end of the trailer overlays a large portion of the bed of the pick-up truck and the protruding hitch tongue of the trailer extends downwardly into the bed of the truck and is coupled to the 5th wheel hitch.
As a result of this coupling arrangement, none of the above described prior art pick-up bed covers can be used on a truck that is utilizing a 5th wheel trailer hitch for towing a trailer. If such a truck is not being used for towing, any of those prior art bed covers could, of course, be used. However, due to the inconvenice, and in many instances, the extreme difficulty associated with removing the bed cover each time the truck is to be used for towing, bed covers are never, to the best of my knowledge, used on trucks that are equipped with 5th wheel trailer hitches, and the beds of such trucks are left uncovered both during towing and non-towing usage.
Therefore, a need exists for a new and useful cover assembly for use on the bed of a pick-up truck which is equipped with a 5th wheel trailer hitch.